jet hypo more optimisation for simple trees.
The calculation of jet gruop products is avoided for simple trees. New specialised IJetProduct implementations are created that either reurn a vector of jets, or merge vectors of jets, according to the circumstances.
JetGroupProductFactory has been expanded to instantiate these new classes.
@ayana @cantel @peter @tamartin ATR-25135 recent_hypo_optimisation.pdf
Edited by Peter Sherwood